Free calculator
Safety Stock Calculator
Enter your normal and worst-case numbers. The calculator shows how many extra units cover a busy stretch and a late delivery at the same time.
Safety stock
84 units
Worst case 140 units, minus normal case 56 units.
Reorder point with this buffer
140 units
Average daily sales × average lead time, plus the safety stock above.
Runs in your browser. Nothing you enter is stored or sent.
The formula
Safety stock = (maximum daily sales × maximum lead time) − (average daily sales × average lead time). It is the gap between your worst case and your normal case.
When to adjust it
This method is cautious, because it assumes your busiest sales and slowest delivery happen together. Hold more for best sellers and unreliable suppliers, and less for slow movers.
Full walkthrough: How to calculate safety stock.